{Reference Type}: Journal Article
{Title}: Bioethanol lignin-rich residue from olive stones for electrospun nanostructures development and castor oil structuring.
{Author}: Rubio-Valle JF;Martín-Alfonso JE;Eugenio ME;Ibarra D;Oliva JM;Manzanares P;Valencia C;
{Journal}: Int J Biol Macromol
{Volume}: 255
{Issue}: 0
{Year}: 2024 Jan 17
{Factor}: 8.025
{DOI}: 10.1016/j.ijbiomac.2023.128042
{Abstract}: This work describes the chemical and structural characterization of a lignin-rich residue from the bioethanol production of olive stones and its use for nanostructures development by electrospinning and castor oil structuring. The olive stones were treated by sequential acid/steam explosion pretreatment, further pre-saccharification using a hydrolytic enzyme, and simultaneous saccharification and fermentation (PSSF). The chemical composition of olive stone lignin-rich residue (OSL) was evaluated by standard analytical methods, showing a high lignin content (81.3 %). Moreover, the structural properties were determined by Fourier-transform infrared spectroscopy, nuclear magnetic resonance, and size exclusion chromatography. OSL showed a predominance of β-β' resinol, followed by β-O-4' alkyl aryl ethers and β-5' phenylcoumaran substructures, high molecular weight, and low S/G ratio. Subsequently, electrospun nanostructures were obtained from solutions containing 20 wt% OSL and cellulose triacetate with variable weight ratios in N, N-Dimethylformamide/Acetone blends and characterized by scanning electron microscopy. Their morphologies were highly dependent on the rheological properties of polymeric solutions. Gel-like dispersions can be obtained by dispersing the electrospun OSL/CT bead nanofibers and uniform nanofiber mats in castor oil. The rheological properties were influenced by the membrane concentration and the OSL:CT weight ratio, as well as the morphology of the electrospun nanostructures.